In developing world regions like the African continent there is a demand for biometric payment verification. Smartcard holders in such regions are not used to memorizing a PIN code. As these regions are still in the process of development, the budget being available for biometric verification tokens and infrastructure is limited. The currently available smartcard infrastructure is contact-based and the card readers do not reliably allow capturing a fingerprint image through the surface of a smartcard when the smartcard is inserted into a reading device, because the whole card surface is covered by the reader and access to the card surface is not feasible while the reader communicates with the smartcard.
Consequently, there is a desire to provide an affordable biometric verification token operating in a contactless and battery-less mode and that is compatible with existing smartcard infrastructure.
Three main problems have been identified with currently available solutions: Power consumption, cost and verification speed.
A limiting factor in power consumption is the fingerprint scanning device itself. Actual capacitive fingerprint sensors perform full area scan of a human fingerprint causing too high integral power consumption.
Another limiting factor in device cost is the requirement for sufficiently large memory to cache the scanned data for later processing. From a cost perspective it is required to reduce the amount of scanned data in order to be able to reduce the required cache memory size.
A further limiting factor is verification speed. Processing the data of a complete area scan requires a computing device that may provide sufficient computational power expressed in MIPS. A majority of the processing time is currently wasted on scan areas that do not contribute to the finally extracted fingerprint features. It is a desire to reduce the required amount of data in order to be able to run the image processing faster.
It may be conventionally known to use a capacitive sensor array in order to detect a fingerprint of a user. Thereby, the human skin conventionally acts as a counterelectrode. The conventional capacitive sensor array requires a surrounding or external metal ring (bezel). Furthermore, according to the conventional capacitive sensor system, the electrodes for which the human skin acts as a counterelectrode are conventionally connected to a ground potential.
It has been observed that the conventional fingerprint sensing system requires particular constructive features which are difficult to implement in particular in mobile devices, such as a smartphone, a smartcard or the like. Furthermore, the conventional systems may require extensive amounts of energy hampering the use of such systems in portable or mobile devices.
Thus, there may be a need for a fingerprint sensing arrangement, in particular fingerprint verification system, for a transponder comprising such a fingerprint verification system and for a method of fingerprint sensing, in particular fingerprint verification, wherein at least some of aforementioned disadvantages are reduced.
In order to meet the above need, an arrangement for fingerprint sensing, in particular fingerprint verification, a transponder including the fingerprint sensing arrangement and a method for fingerprint sensing are provided, as specified by the independent claims. The dependent claims specify particular embodiments of the present invention.